(a) Field of the Invention
The present invention relates to a continuous variable valve lift apparatus, more particularly, a continuous variable valve lift apparatus that can adjust a valve lift amount in response to an operational state of an engine.
(b) Description of the Related Art
Generally, an automotive engine includes a combustion chamber in which fuel burns to generate power. The combustion chamber is provided with an intake valve for supplying a gas mixture containing the fuel and an exhaust valve for expelling the burned gas. The intake and exhaust valves open and close the combustion chamber by a valve lift apparatus connected to a crankshaft.
A conventional valve lift apparatus has a fixed valve lift amount using a cam formed in a predetermined shape. Therefore, it is impossible to adjust the amount of a gas mixture that is being introduced or exhausted. Therefore, the engine does not run at its optimal efficiency in various driving ranges.
For example, as a conventional art, if a valve lift apparatus is designed to optimally respond to a low driving speed, the valve open time and amount are not sufficient for a high speed driving state. On the contrary, when the valve lift apparatus is designed to optimally respond to a high speed driving state, an opposite phenomenon occurs in the low speed driving state.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.